Kinder, Gentler Dams?

“Off-channel” reservoirs – that don’t block river courses – are all the rage among would-be dam builders these days. In the September 9, 2008 issue of High Country News , I wrote an article, “A river runs near it,” examining two potential off-channel projects in Yakima, Washington (Black Rock Reservoir), and Fort Collins (Glade Reservoir, a.k.a. NISP, the Northern Integrated Supply Project).

Check out the full story at hcn.org, but here’s a little taste of why environmental critics aren’t buying the hype:

Glade is “the same (as any dam) in terms of impact to the flow regime,” says Mark Easter, a spokesman for the Save the Poudre coalition. Although Glade is supposed to bolster low river flows, some worry that its diminishing effects on high flows could threaten plans for a new kayak park.

Easter is also doubtful about the agricultural benefits. A draft environmental impact statement says that constructing Glade would save 33,600 to 69,000 acres of farmland from development and the loss of water rights. But Easter calculates that the reservoir would make it possible to build at least 20,000 acres’ worth of new subdivisions and encourage breakneck growth so towns could repay their debts.

Up in Washington, the environmental benefits of Black Rock appear to pale in comparison with its costs. According to the draft environmental impact statement, the project would provide only about 16 cents in benefits to fish and farmers for every dollar spent. That doesn’t include regional economic growth and tourism, but the skewed cost-benefit ratio has united reservoir opponents.

Phil Rigdon, the Yakama Nation’s deputy director of natural resources, says the tribe is not opposed to a new reservoir. But his agency is skeptical about Black Rock’s potential for salmon restoration. More significant habitat improvements and new fish-passage devices on the existing dams would also need to be built before the release of water from Black Rock could help salmon, Rigdon says. “We’re saying you need a full package; otherwise, don’t sell it as a fish project.”